South Korean stocks ended Tuesday's trading session virtually unchanged as expectations that the market will be able to maintain upward momentum collided with jitters related to Japan's quantitative easing (QE). The South Korean won lost against the U.S. dollar. The benchmark Korea Composite Stock Price Index (KOSPI), which started off in positive territory, fluctuated throughout most of the day before ending at 1,946.91, up an imperceptible 0.03 percent, or 0.55 point, from Monday's close.